iPhone 5 while studying abroad....(I ready the guides in the sidebar but still have additional questions)

I'm going to be studying in Hong Kong from the beginning of January to the end of may. I've heard about buying a crappy phone when I get there and getting prepaid minutes, but wanted to know if thats my best option. Being an iPhone user in the US, I can't imagine not having a smartphone for 5 months. Is there any affordable options I should be looking into? Can I buy a sim card online while in the US so I have it before I get there? Any suggestions in general about which non-smart phone to get and which prepaid card?

I know these might be annoying questions, but when searching online its hard to find the most up-to-date answers and I would really appreciate some reddit feedback. Thanks!